/*
 * @(#)Group.java 1.20 04/01/12
 * 
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved. SUN
 * PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.tools.doclets.internal.toolkit.util;

import com.sun.tools.doclets.internal.toolkit.*;
import com.sun.javadoc.*;
import java.util.*;

/**
 * Process and manage grouping of packages, as specified by "-group" option on
 * the command line.
 * <p>
 * For example, if user has used -group option as -group "Core Packages"
 * "java.*" -group "CORBA Packages" "org.omg.*", then the packages specified on
 * the command line will be grouped according to their names starting with
 * either "java." or "org.omg.". All the other packages which do not fall in the
 * user given groups, are grouped in default group, named as either "Other
 * Packages" or "Packages" depending upon if "-group" option used or not at all
 * used respectively.
 * </p>
 * <p>
 * Also the packages are grouped according to the longest possible match of
 * their names with the grouping information provided. For example, if there are
 * two groups, like -group "Lang" "java.lang" and -group "Core" "java.*", will
 * put the package java.lang in the group "Lang" and not in group "Core".
 * </p>
 * 
 * This code is not part of an API. It is implementation that is subject to
 * change. Do not use it as an API
 * 
 * @author Atul M Dambalkar
 */
public class Group {
	
	private static Group instance;
	
	/**
	 * Map of regular expressions with the corresponding group name.
	 */
	private Map regExpGroupMap = new HashMap();
	
	/**
	 * List of regular expressions sorted according to the length. Regular
	 * expression with longest length will be first in the sorted order.
	 */
	private List sortedRegExpList = new ArrayList();
	
	/**
	 * List of group names in the same order as given on the command line.
	 */
	private List groupList = new ArrayList();
	
	/**
	 * Map of non-regular expressions(possible package names) with the
	 * corresponding group name.
	 */
	private Map pkgNameGroupMap = new HashMap();
	
	/**
	 * The global configuration information for this run.
	 */
	private final Configuration configuration;
	
	/**
	 * Since we need to sort the keys in the reverse order(longest key first),
	 * the compare method in the implementing class is doing the reverse
	 * comparison.
	 */
	private static class MapKeyComparator implements Comparator {
		public int compare(Object key1, Object key2) {
			return ((String) key2).length() - ((String) key1).length();
		}
	}
	
	private Group(Configuration configuration) {
		this.configuration = configuration;
	}
	
	public static Group getInstance(Configuration configuration) {
		if (instance == null) {
			instance = new Group(configuration);
		}
		return instance;
	}
	
	/**
	 * Depending upon the format of the package name provided in the "-group"
	 * option, generate two separate maps. There will be a map for mapping
	 * regular expression(only meta character allowed is '*' and that is at the
	 * end of the regular expression) on to the group name. And another map for
	 * mapping (possible) package names(if the name format doesen't contain meta
	 * character '*', then it is assumed to be a package name) on to the group
	 * name. This will also sort all the regular expressions found in the
	 * reverse order of their lengths, i.e. longest regular expression will be
	 * first in the sorted list.
	 * 
	 * @param groupname The name of the group from -group option.
	 * @param pkgNameFormList List of the package name formats.
	 */
	public boolean checkPackageGroups(String groupname, String pkgNameFormList) {
		StringTokenizer strtok = new StringTokenizer(pkgNameFormList, ":");
		if (groupList.contains(groupname)) {
			configuration.message.warning("doclet.Groupname_already_used",
					groupname);
			return false;
		}
		groupList.add(groupname);
		while (strtok.hasMoreTokens()) {
			String id = strtok.nextToken();
			if (id.length() == 0) {
				configuration.message.warning("doclet.Error_in_packagelist",
						groupname, pkgNameFormList);
				return false;
			}
			if (id.endsWith("*")) {
				id = id.substring(0, id.length() - 1);
				if (foundGroupFormat(regExpGroupMap, id)) {
					return false;
				}
				regExpGroupMap.put(id, groupname);
				sortedRegExpList.add(id);
			} else {
				if (foundGroupFormat(pkgNameGroupMap, id)) {
					return false;
				}
				pkgNameGroupMap.put(id, groupname);
			}
		}
		Collections.sort(sortedRegExpList, new MapKeyComparator());
		return true;
	}
	
	/**
	 * Search if the given map has given the package format.
	 * 
	 * @param map Map to be searched.
	 * @param pkgFormat The pacakge format to search.
	 * 
	 * @return true if package name format found in the map, else false.
	 */
	boolean foundGroupFormat(Map map, String pkgFormat) {
		if (map.containsKey(pkgFormat)) {
			configuration.message.error("doclet.Same_package_name_used",
					pkgFormat);
			return true;
		}
		return false;
	}
	
	/**
	 * Group the packages according the grouping information provided on the
	 * command line. Given a list of packages, search each package name in
	 * regular expression map as well as package name map to get the
	 * corresponding group name. Create another map with mapping of group name
	 * to the package list, which will fall under the specified group. If any
	 * package doesen't belong to any specified group on the comamnd line, then
	 * a new group named "Other Packages" will be created for it. If there are
	 * no groups found, in other words if "-group" option is not at all used,
	 * then all the packages will be grouped under group "Packages".
	 * 
	 * @param packages Packages specified on the command line.
	 */
	public Map groupPackages(PackageDoc[] packages) {
		Map groupPackageMap = new HashMap();
		String defaultGroupName = (pkgNameGroupMap.isEmpty() && regExpGroupMap.isEmpty())
				? configuration.message.getText("doclet.Packages")
				: configuration.message.getText("doclet.Other_Packages");
		// if the user has not used the default group name, add it
		if (!groupList.contains(defaultGroupName)) {
			groupList.add(defaultGroupName);
		}
		for (int i = 0; i < packages.length; i++) {
			PackageDoc pkg = packages[i];
			String pkgName = pkg.name();
			String groupName = (String) pkgNameGroupMap.get(pkgName);
			// if this package is not explicitly assigned to a group,
			// try matching it to group specified by regular expression
			if (groupName == null) {
				groupName = regExpGroupName(pkgName);
			}
			// if it is in neither group map, put it in the default
			// group
			if (groupName == null) {
				groupName = defaultGroupName;
			}
			getPkgList(groupPackageMap, groupName).add(pkg);
		}
		return groupPackageMap;
	}
	
	/**
	 * Search for package name in the sorted regular expression list, if found
	 * return the group name. If not, return null.
	 * 
	 * @param pkgName Name of package to be found in the regular expression
	 *        list.
	 */
	String regExpGroupName(String pkgName) {
		for (int j = 0; j < sortedRegExpList.size(); j++) {
			String regexp = (String) sortedRegExpList.get(j);
			if (pkgName.startsWith(regexp)) {
				return (String) regExpGroupMap.get(regexp);
			}
		}
		return null;
	}
	
	/**
	 * For the given group name, return the package list, on which it is mapped.
	 * Create a new list, if not found.
	 * 
	 * @param map Map to be searched for gorup name.
	 * @param groupname Group name to search.
	 */
	List getPkgList(Map map, String groupname) {
		List list = (List) map.get(groupname);
		if (list == null) {
			list = new ArrayList();
			map.put(groupname, list);
		}
		return list;
	}
	
	/**
	 * Return the list of groups, in the same order as specified on the command
	 * line.
	 */
	public List getGroupList() {
		return groupList;
	}
}
